"The boat in which these improvements have been introduced is 86 feet long by 11 feet beam and 5 feet 6 inches deep. She is fitted with compound engines having 22 inch and 12-1/2 inch cylinders, with a 12 inch stroke, and making 520 revolutions per minute when running at full speed. She is propelled by a three-bladed screw 5 feet 6 inches in diameter and 5 feet pitch. Put through some evolutions with the view of testing her steering powers, the double rudder arrangement was found to answer exceedingly well, and she turned a circle of a diameter equal to about three times her own length in 1 minute 15 seconds. She turned equally well either going ahead or astern, and in fact her steering capabilities were satisfactorily demonstrated. The new arrangement for carrying off the smoke also answered very well, with the exception that the heated gases occasionally swept the deck, which objectionable result will be avoided in future boats."
These boats are to be armed with spar torpedoes, and with the Whitehead fish torpedo, the cradles and fittings for which are shown at Fig. 161.
_The Fastest Vessel in the World._--Another type of torpedo boat, of which one of the same dimensions has been built by this firm for the English government, is shown at Fig. 162. This vessel is as yet the fastest vessel in the world. The trials with this boat were made in March of this year, and were as follows:--
Runs. Time, Knots Knots Min. sec. per hour. per hour.
First 2 37 = 22·93} Second 3 2 = 19·78} Mean of first pair = 21·35
Third 2 33 = 23·53} Fourth 2 55 = 20·57} Mean of second pair = 22·05
Fifth 2 30 = 24·00} Sixth 2 56 = 20·45} Mean of third pair = 22·23
giving as a mean 21·93 knots per hour, or 25-1/4 statute miles. The boat was fully equipped for active service, i.e. with a load of 6-3/4 tons on board. It was found during the trial that at speeds of 17 and 19 knots the vibration of the boat was considerable, but when running over 20 knots it was hardly perceptible; the excessive vibration taking place when the revolutions of the engines became a multiple of the natural vibration of the boat.
Torpedo boats are at the present time being built by this firm for the English, French, Spanish, Austrian, and Italian governments.